It doesn't matter if scope clauses will eventually change or not. Skywest and TSA have recently re-affirmed their positions in the MRJ90, in addition to their E2 orders. That means they will not be ordering CRJs any time soon == effective lost sales for Bombardier.
And by the way, Bombardier is floating the CRJ re-engine concept:
Bombardier looks at upgrade for regional jets
Thursday, January 26, 2017
MONTREAL -- Bombardier Inc. is weighing options for a new engine on its regional jets in a move that could give its commercial aircraft lineup a boost until its flagship C Series starts making money, people familiar with the matter said.
The plane maker is analyzing how it can update its family of Canadair Regional Jets to make them more enticing for airline customers in the years ahead, according to the people, who asked not to be named because they aren't authorized to speak publicly about the review. In the absence of funds for an all-new, clean-sheet design for a regional jet, the company is exploring a big overhaul of its existing 60- to 100-seat CRJ planes centred on new engines, the people said.
"[Bombardier has] to do something" with the CRJ aircraft, said Richard Aboulafia of aerospace consultancy Teal Group. "The idea of using an eighties vintage engine in the next century when everyone else has adopted new technology, that's just a non-starter." ...
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Bombardier looking at options for revamp of regional jet, sources say | The Globe and Mail